The sea urchin

About this heritage

The sea urchin, Paracentrotus lividus (Lamark, 1816), is a regular, dark-colored echinoderm with a tendency towards black, green, violet brown, and reddish. It is the most common species in Spain and much of Europe, and the commercial sea urchin species par excellence. It has robust sharp and short spines, with which they move slowly through the seabed, and when they fall, they show a body divided into groups of plates.

Its body is not entirely spherical, but rather flattened, and slightly flat in the belly area. The female gonads are bright yellow or orange while the male gonads are yellow or yellowish-brown and whitish.

Although its maximum size is commonly described as 75mm, urchins with larger sizes have been reported, particularly in Galician waters, reaching up to 95mm, albeit large individuals are scarce.

Their capture requires time and patience because of their spines and their habitat; they tend to be in rocky and dark locations of the intertidal and subtidal areas, often deep of up to 30 meters, so they can only be caught one by one, and usually, by professional divers. The minimum fishing legal size is 5.5 centimeters.

They are benthic animals that move slowly on the marine substrate, thanks to the combined actions of their tube feet and mobile spines. They are primarily considered herbivores and act as regulators of seaweed biomass. They covered themselves with shells, stones, and algae to defend and avoid intense light.

Like all echinoids, sea urchins are dioecious. They have five gonads suspended along the internal face of each one of the interambulacral zones of the shell. They release eggs and sperm into the seawater, where fertilization takes place.

To learn more

The class echinoid (Echinoidea) belongs to the phylum of the Echinoderms. The name Echinoidea, which means "similar to a hedgehog (porcupine)," refers to the mobile spines (spikes) that cover the body of these animals, and they are named sea urchins.

Around 950 species have been described worldwide.

There are two types of sea urchins, differentiating the external structure. One type is the regular urchin with a nearly spherical body that can be divided into two hemispheres, the aboral and the oral, which are radially arranged, and endowed with a series of mobile spines. The other type is the irregular sea urchin or bilateral sea urchin, which includes the heart or spatangoida urchins and the sand dollars or sea biscuits urchins. Most of the characteristics of these animals are related to their ability adaptation for excavation in the sand.

In Galicia, the sea urchin (Paracentrotus lividus) is considered a specific resource, and its capture is regulated by management plans approved by the Ministry of the Sea. It can be caught on foot or from a boat using for help a mirror or an aquascope (bathyscope) and using fishing devices called "bicheiro" and "forquita", which are long poles with a metal hook or a fork at the end, respectivelly; however, these artifacts can only be used in depths of no more than five meters. It can also be extracted by diving in apnea or freediving, so by diving under water without the use of breathing apparatus. Fishing or catching season is concentrated from October to April.

The main traditional consumer countries are Japan as the world's leading customer of sea urchins and France. In both countries, urchins are very appreciated constituting a luxury product for its high price. Other ones with a consumer tradition are China, Italy, and the USA, where the Italian and Eastern communities are the ones that promote its consumption.

From the sea urchin, only the gonad, which is the interior, is eaten. The classic way to eat it is raw, opening the sea urchin carefully and using a spoon. By eating it raw, we will appreciate its intense sea flavor.

The modern cuisine incorporates them to sauces to accompany different fish dishes and multiply its sea flavor. They are also prepared in preserves, patés, scrambled or mixed dishes, and mayonnaises.

To open it, manipulate it with a kitchen cloth, take the urchin by its lower part and with the help of kitchen scissors, cut the central part to enlarge the cutting area and prevent the spines from detaching towards the inside.

When handling urchins, it is easy to sting or cut yourself with the spines; these are esily breakable, and if it gets in your skin, you should remove it to avoid infections.

In the last five year, the average catch of sea urchin (Paracentrotus lividus) was about 99,763.70 kg/year, which represents 27.38 % of the total annual catch in the Bayonne fish market. This generated, for the same period, an average income of € 524,765.94 per year. The marketing of this species accounted for approximately 25% of total income over the last 5 years, making it a very important resource for this entity.

To know it better

The class echinoid (Echinoidea) belongs to the phylum of the Echinoderms. The name Echinoidea, which means "similar to a hedgehog (porcupine)," refers to the mobile spines (spikes) that cover the body of these animals, and they are named sea urchins.

Around 950 species have been described worldwide.

There are two types of sea urchins, differentiating the external structure. One type is the regular urchin with a nearly spherical body that can be divided into two hemispheres, the aboral and the oral, which are radially arranged, and endowed with a series of mobile spines. The other type is the irregular sea urchin or bilateral sea urchin, which includes the heart or spatangoida urchins and the sand dollars or sea biscuits urchins. Most of the characteristics of these animals are related to their ability adaptation for excavation in the sand.

The Paracentrotus lividus (Lamark, 1816) is a regular sea urchin that presents browns, blacks, purples, greens, whites, or reds colors although some exhibit different mixed colors. Their maximum size is around 75mm. The shape of the body of the urchins is round with long spines. These are used for diferent purposes, including moving, protecting themselves, and even trapping specific food particles from the surface. They live on the seabed.

Depending on the season, thousands and thousands of kilos of sea urchins can be found in the Baiona fish market.

The sea urchin extraction campaign runs from October to April, coinciding with the time when their gonads are more developed, and a ban shall is established from May to September.

As a food, urchins can be eaten baked and raw with a few drops of lemon, in scrambled or mixed dishes, or salads.